Valve guide insert with frictional pre-broach retention feature

ABSTRACT

A valve guide insert for lining and relining a valve guide bore in an internal combustion engine includes a one-piece, thin-walled, cylindrically-shaped metallic tube made from reformable bearing material having first and second ends and an intermediate portion. An inwardly tapered portion is disposed at the first end, wherein an end diameter of the inwardly tapered portion is less than an outer diameter of a valve guide bore, and wherein the outer diameter of the intermediate section is greater than an inner diameter of a valve guide bore. A longitudinal slit is included having a stepped portion along a length of the longitudinal slit. An interference portion is disposed proximate the second end, wherein the interference portion is configured to substantially secure the valve guide insert within a valve guide bore.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/831,794 filed on Jun. 6, 2013, entitled “VALVE GUIDE INSERT WITH FRICTIONAL PRE-BROACH RETENTION FEATURE,” the entire disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a valve guide insert for use in internal combustion engines and the like, and in particular to a thin-walled valve guide insert.

Valve guide inserts are commonly used in the construction and rebuilding of cylinder heads in internal combustion engines. More particularly, valve guide inserts are used to provide a wear resistant bearing surface between cylinder heads and the associated valves. Through extended use, valve guides within internal combustion engines can become worn, thereby allowing the associated valve to become sloppy within an associated cylinder. This sloppiness may result in improper seating of the valve or even the failure of the engine.

Cylinder heads associated with internal combustion engines are typically cast from iron or other non-durable metals. Valve guide inserts have become useful within the vehicle engine manufacturing industry by providing a hardened bearing surface between the valve guides and the associated valves, thereby increasing the useful life of the valve guides. Valve guide inserts have also become useful in the engine refurbishing industry by allowing for a worn guide to be broached and a valve guide insert to be inserted within the resurfaces and/or resized valve guide bore, thereby allowing for the continued use of the engine.

Heretofore, valve guide inserts were tubular shaped members formed of a hardened wear resistant metal. Typically, the valve guide inserts were press-fit into a valve guide bore of a cylinder head by way of a mechanical device that forcibly inserted the valve guide inserts within the valve guide bores. A broaching tool was then forced through the valve guide insert to form an interior bore for guiding the associated valve, as well as to create a tight fit of the valve guide insert within the valve guide floor. Hand-inserted valve guide inserts are also used and eliminate the need for mechanical inserting devises, thereby making the process more efficient and less costly.

A problem associated with the use of conventional hand-inserted valve guide inserts is the retention of the valve guide inserts within the valve guide bore before using the broaching tool. Depending upon the application, the valve guide insert may be inserted into the valve guide bore, either from above or below, to best take advantage of the various geometries and configurations of internal combustion engines. As a result, a valve guide insert that is inserted from below can have a tendency of falling out of the valve guide bore before the broaching tool can be used. Also, where several valve guide inserts are inserted into several respective valve guide bores, the use of the broaching tool in one of the valve guide bores may cause one or more of the remaining unbroached valve guide inserts to slide through and/or fall out of the valve guide bore due to vibrations caused by the broaching tool.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, a valve guide insert for lining and relining a valve guide bore in an internal combustion engine includes a one-piece, thin-walled, cylindrically-shaped metallic tube made from reformable bearing material having first and second ends and an intermediate section that extends between the first and second ends. An inwardly-tapered portion is disposed at the first end, wherein an end diameter of the valve guide insert at the inwardly tapered portion is less than an inner diameter of a valve guide bore, and wherein the outer diameter of the intermediate section is greater than an inner diameter of a valve guide bore. A longitudinal slit is disposed along the length of the valve guide insert. An interference portion is disposed proximate the second end, wherein the interference portion is configured to substantially secure the valve guide insert within a valve guide bore.

In another embodiment, a valve guide insert for lining and relining a valve guide bore in an internal combustion engine includes a one-piece, thin-walled, cylindrically-shaped metallic tube made from reformable bearing material having first and second ends and an intermediate portion. An inwardly tapered portion is disposed at the first end, wherein an end diameter of the valve guide insert at the inwardly-tapered portion is less than an inner diameter of a valve guide bore, and wherein the outer diameter of the intermediate section is greater than an inner diameter of a valve guide bore. A longitudinal slit is disposed along the length of the valve guide insert, wherein the longitudinal slit includes a stepped portion, and an interference portion is disposed on at least a portion of an outer surface of the valve guide insert, the interference portion having a roughness parameter of greater than about 32 Ra.

In yet another embodiment, a valve guide insert for lining and relining a valve guide bore in an internal combustion engine includes a formed cylindrically-shaped tube having a substantially consistent wall thickness. The cylindrical tube can have first and second ends, first and second edges that extend between the first and second ends, and an intermediate portion defined within the first and second ends and first and second edges. The cylindrical tube is shaped such that the first and second edges define a longitudinal slit along the length of the cylindrical tube. An outwardly flared portion of the cylindrical tube is disposed proximate one of the first and second ends.

In other various embodiments, the apparatus described herein can be incorporated into a method for broaching a valve guide insert to shape the interior surface of a valve guide insert within a valve guide bore of a cylinder head of a combustion engine.

These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of a valve guide insert installed in a valve guide bore of a cylinder head of a combustion engine;

FIG. 2 is a side elevation view of one embodiment of a valve guide insert embodying the present invention;

FIG. 3 is an elevation view of the inner surface of the valve guide insert of FIG. 2 with the valve guide insert in an unrolled state;

FIG. 4 is an edge elevation view of the valve guide insert of FIG. 3;

FIG. 5 is a perspective view of the valve guide insert of FIG. 2;

FIG. 6 is an end elevation view of the valve guide insert of FIG. 2;

FIG. 7 is a side elevation view of another embodiment of a valve guide insert embodying the present invention;

FIG. 8 is an elevation view of the inner surface of the valve guide insert of FIG. 7 with the valve guide insert in an unrolled state;

FIG. 9 is an edge elevation view of the valve guide insert of FIG. 8;

FIG. 10 is a perspective view of the valve guide insert of FIG. 7;

FIG. 11 is an end elevation view of the valve guide insert of FIG. 7;

FIG. 12 is a side elevation view of another embodiment of a valve guide insert embodying the present invention;

FIG. 13 is an elevation view of the inner surface of the valve guide insert of FIG. 12 with the valve guide insert in an unrolled state;

FIG. 14 is an edge elevation view of the valve guide insert of FIG. 13;

FIG. 15 is a perspective view of the valve guide insert of FIG. 12;

FIG. 16 is an end elevation view of the valve guide insert of FIG. 12;

FIG. 17 is a side elevation view of another embodiment of a valve guide insert embodying the present invention;

FIG. 18 is an elevation view of the inner surface of the valve guide insert of FIG. 17 with the valve guide insert in an unrolled state;

FIG. 19 is an edge elevation view of the valve guide insert of FIG. 18;

FIG. 20 is a perspective view of the valve guide insert of FIG. 17;

FIG. 21 is an end elevation view of the valve guide insert of FIG. 17;

FIG. 22 is a side elevation view of another embodiment of a valve guide insert embodying the present invention;

FIG. 23 is an elevation view of the inner surface of the valve guide insert of FIG. 22 with the valve guide insert in an unrolled state;

FIG. 24 is an edge elevation view of the valve guide insert of FIG. 23;

FIG. 25 is a perspective view of the valve guide insert of FIG. 22; and

FIG. 26 is an end elevation view of the valve guide insert of FIG. 22.

DETAILED DESCRIPTION

For purposes of description herein the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the device as oriented in FIG. 1. However, it is to be understood that the device may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

As shown in FIGS. 1-6, reference numeral 10 generally designates a valve guide insert for lining and relining a valve guide bore 12 in an internal combustion engine (not shown). The internal combustion engine includes a valve section such as a cylinder head 14 that includes a valve having a valve stem 18 and a valve head 20. The valve guide bore 12 is configured to support the valve stem 18 for reciprocal motion. The valve guide insert 10 includes a thin-walled, generally one-piece, cylindrically-shaped metallic tube 22 having a first end 24, a second end 26, an intermediate or long section 28 located between the first end 24 and the second end 26, and an inwardly tapered portion 30 disposed at the first end 24 where the diameter at a narrow end 32 of the inwardly tapered portion 30 of the first end 24 is smaller than the diameter of the valve guide insert 10 distal from the inwardly tapered portion 30.

As shown in FIGS. 2-6, the tube 22 further includes a longitudinally extending slit 34 that extends along the entire length of the tube 22. The slit 34 includes a step 36 or offset along its length. The slit 34 allows for compression of the tube 22 and reduction in the associated diameters of the tube 22 as the valve guide insert 10 is inserted into the valve guide bore 12, and also allows for expansion of the associated diameters of the tube 22 as the valve guide insert 10 is broached. In the various embodiments, the slit 34 is defined between first and second edges 38, 40 of the metallic member that forms the tube 22 of the valve guide insert 10. The intermediate portion or long section 28 is defined between the first and second ends 24, 26 and the first and second edges 38, 40 forms the tube 22. When the metal member is rolled to form the tube 22, the first and second edges 38, 40 define the slit 34 of the valve guide insert 10. In various embodiments, it is contemplated that the longitudinal slit 34 can be a linear slit 34 having no step 36 included therein.

Referring again to FIG. 1, the valve guide insert 10 is adapted for insertion into the valve guide bore 12 of a cylinder head 14 for the internal combustion engine. The valve guide insert 10 is adapted for use in a cylinder head 14 with a valve guide bore 12 machined therein. The cylinder head 14 includes an exposed shoulder portion 52 located at one end of the valve guide bore 12. Typically, the exposed shoulder 52 will be integral with the cylinder head 14 and machined to the proper dimensions. The valve stem 18 of the valve passes through the valve guide bore 12 during assembly. A valve spring 54 encircles the exposed shoulder 52 of the cylinder head 14, and the valve 16 is retained therein by a pair of valve keepers (not shown). The valve stem 18 extends downward and terminates in the valve head 20 (or valve flange) that seats against a valve seat 56. The valve seat 56 is typically machined into the lower surface of the cylinder head 14. The valve 16 opens into an engine combustion chamber (not shown). The valve spring 54 retains the valve 16 in a closed position relative to the valve seat 56, except when the valve 16 is forced downward by a rocker arm (not shown) or other biasing mechanism of the engine.

Referring again to FIGS. 1-6, the valve guide insert 10 is configured to have a first outer diameter 70 at the narrow end 32 of the inwardly tapered portion 30 that is smaller than the inner diameter 72 of the valve guide bore 12 such that the valve guide insert 10 can be inserted into the valve guide bore 12. A second outer diameter 74 of the valve guide insert 10 distal from the inwardly tapered portion 30 is greater than an inner diameter 72 of the valve guide bore 12. In this manner, as the valve guide insert 10 is inserted in the valve guide bore 12, the valve guide insert 10 is compressed and the slit 34 becomes substantially closed. The configuration of the metallic material of the valve guide insert 10 is such that the valve guide insert 10 tends to retain its original diameter such that the valve guide insert 10 is biased outwardly against the inner diameter 72 of the valve guide bore 12 thereby creating an at least partial compression and/or friction fit between the valve guide insert 10 and the valve guide bore 12.

As illustrated in FIGS. 1-6, the interior surface 80 of the tube 22 can include oil retaining grooves 82 having a generally spiral pattern. The spiral pattern is typically disposed on the interior surface 80 of the valve guide insert 10 and is created on the interior surface 80 of the valve guide insert 10 during the process for rolling the material into the generally cylindrical shape that characterizes the valve guide insert 10. As will be discussed below, other marking or etching patterns can be installed in or on the interior of outer surface 122 of the valve guide insert 10 as the metallic material is rolled into the cylindrical shape. Once the valve guide insert 10 is disposed within the valve guide bore 12, a broaching tool (not shown) is used to shape the interior surface 80 of the valve guide insert 10 within the valve guide bore 12 to create the desired interior diameter necessary for the reciprocal movement of the valves 16. The broaching apparatus and method for broaching the valve guide insert 10 is generally disclosed in U.S. Pat. No. 6,470,846 entitled BROACH TOOL AND METHOD OF REPAIR to Kammeraad et al., the entirety of which is hereby incorporated by reference.

In the various embodiments, the valve guide insert 10 is generally made of a substantially malleable metallic material that can include bronze, copper, alloys thereof, or other substantially malleable metallic material that can be formed through the use of the broaching tool.

As illustrated in FIGS. 1-6, the valve guide insert 10 can also include an outwardly flared portion 90 at the second end 26 of the valve guide insert 10, where a third outer diameter 92 of the valve guide insert 10 at a wide end 94 of the flared portion 90 is greater than the second outer diameter 74 of the valve guide insert 10 distal to the flared portion 90. In this manner, the flared portion 90 of the valve guide insert 10 in connection with the flexibility of the valve guide insert 10 provided by the slit 34, provides an additional compression and/or frictional resistance fit when the valve guide insert 10 is inserted into the valve guide bore 12. In this manner, the valve guide insert 10 is inserted into the valve guide bore 12, such that the flared portion 90 of the valve guide insert 10 engages either a first or second end 24, 26 of the valve guide bore 12. As the valve guide insert 10 is pressed into the valve guide bore 12, the valve guide bore 12 biases the flared portion 90 in an inward direction.

According to the various embodiments, the valve guide insert 10 is made from a metallic sheet that is rolled into a cylindrical form. In this manner, the valve guide insert 10 is configured to substantially retain and tends to retain its originally rolled cylindrical shape. Accordingly, as the flared portion 90 of the valve guide insert 10 is compressed inward by one of the ends of the valve guide bore 12, the valve guide insert 10 biases against the valve guide bore 12 at least at the flared portion 90 to create a compression and/or frictional fit such that the valve guide insert 10 substantially remains within the valve guide bore 12. In this way, additional valve guide inserts 10 can be inserted into the remaining valve guide bores 12 of the combustion engine and the broaching tool can be used on the various valve guide inserts 10, while the valve guide inserts 10 substantially retain their position within each of their respective valve guide bores 12. This compression or frictional fit can make the entire process of inserting the valve guide inserts 10 and using the broaching tool a more efficient process where all of the valve guide inserts 10 can be positioned in one step 36 and all of the valve guide inserts 10 can be broached in a single subsequent step 36.

As shown in FIG. 1, the flared portion 90 can extend approximately 0.125″ from the end of the valve guide insert 10. Also, the third outer diameter 92 of the valve guide insert 10 at the wide end 94 of the flared portion 90 can be within the range of about 0.032″ greater than the second outer diameter 74 of the valve guide insert 10 distal to the flared portion 90. In various alternate embodiments, the length of the flared portion 90 and the third outer diameter 92 at the wide end 94 of the flared portion 90 can be increased or decreased depending upon the particular application or design needs involved.

Referring now to FIGS. 6-10 of the illustrated embodiment, the slit 34 of the valve guide insert 10 can include a tabbed portion 100 at the second end 26 of the valve guide insert 10, wherein the width of the slit 34 is narrower at the tabbed portion 100. It is contemplated that the tabbed portion 100 can extend from the second end 26 approximately 0.125 inches. It is further contemplated that the tabbed portion 100 can extend into the slit 34 approximately 0.005 inches on each side of the slit 34. It should be understood that different dimensions are also contemplated.

Referring now to FIGS. 11-15, in an alternate embodiment, the slit 34 of the valve guide insert 10 can include a tapered portion 110 located at the second end 26 of the valve guide insert 10. The slit 34 at the tapered portion 110 generally narrows from a first width 112 to a second width 114, wherein the first width 112 is the same width as the portions of the slit 34 distal from the tapered portion 110, and wherein the second width 114 is narrower than the first width 112.

Referring again to the embodiments illustrated in FIGS. 6-15, the embodiments of the valve guide insert 10 that contain either the tabbed portion 100 or tapered portion 110 of the slit 34 can serve to hold the valve guide insert 10 within the valve guide bore 12 during the broaching process. The tabbed portions 100 or tapered portions 110 are configured such that when the valve guide insert 10 is inserted into the valve guide bore 12, the slit 34 is substantially closed at the first and second ends 24, 26. However, the configuration of the slit 34 with the narrower width at the tabbed portion 100 or tapered portions 110 and the larger width of the slit 34 along the remaining length of the valve guide insert 10 forms the valve guide insert 10 into a generally tapered shape when the valve guide insert 10 is placed within the valve guide bore 12. In this manner, the valve guide insert 10 is compressed to a smaller diameter at the first end 24 than at the second end 26. This tapered configuration creates a generally snug fit between the valve guide insert 10 and the valve guide bore 12 such that the valve guide insert 10 is positioned within the valve guide bore 12 by creating a sufficient friction and/or compression fit such that the valve guide insert 10 remains substantially in place during the broaching process. Also, the additional surface area of the valve guide insert 10 located at the second end 26 in these embodiments provides additional surface area that can substantially secure the valve guide insert 10 within the valve guide bore 12. In this embodiment, the valve guide insert 10 can be formed into a generally cylindrical shape, or a tapered geometry, without losing the structural benefits of having a generally tapered valve guide insert 10 for retention within the valve guide bore 12.

In alternate embodiments, the configurations of the valve guide insert 10 having the tabbed portions 100 or tapered portions 110 of the slit 34 can also include the flared portion 90, as discussed above. When the flared portion 90 of the valve guide insert 10 is formed in conjunction with the valve guide insert 10 having either the tapered portion 110 or the tabbed portion 100, the flared portion 90 can be formed with minimal loss of material as a result of expanding the diameter of the valve guide insert 10 to form the flared portion 90. Typically, when the flared portion 90 of the valve guide insert 10 is created and the slit 34 has a substantially consistent width, as the flared portion 90 is formed, the thickness of the material at the flared portion 90 can become thinner than the cross-sectional thickness of the remaining portions of the valve guide insert 10. The inclusion of the tabbed portion 100 or the tapered portion 110 tends to minimize the thinning of the valve guide insert 10 at the flared portion 90 such that the material of the flared portion 90 can have a substantially consistent thickness.

Referring now to FIGS. 16-20 of the illustrated embodiments, the valve guide insert 10 can also include an interference portion, where the interference portion can include an anaerobic adhesive retaining compound 120 that is disposed on at least a portion of an outer surface 122 of the valve guide insert 10. The anaerobic adhesive retaining compound 120 is in the form of a liquid when applied. When sealed between metals, such that the anaerobic adhesive retaining compound 120 is isolated from oxygen and also in the presence of metal ions, such as copper or iron, the anaerobic adhesive retaining compound 120 cures. By way of explanation and not limitation, when a valve guide insert 10 that has an applied layer of the anaerobic adhesive retaining compound 120 is inserted into the valve guide bore 12 defined by the metallic block of the cylinder head 14, the anaerobic adhesive retaining compound 120 rapidly cures or hardens to form a cross-linked plastic with rugged adhesion to many metals. When cured, the anaerobic adhesive retaining compound 120 has high shear strength. In addition, as the anaerobic adhesive retaining compound 120 cures, the anaerobic adhesive retaining compound 120 substantially fills the microscopic gaps between interfacing metallic materials to positively lock and seal the metallic materials, preventing lateral movement and substantially protecting the joint from corrosion that can result from moisture, gasses and fluids. The anaerobic adhesive retaining compound 120 used in such an embodiment is similar to the anaerobic adhesive retaining compounds 120 manufactured by LOCTITE®. In the various embodiments, the retaining compound 120 can be applied to the valve guide insert 10 before the valve guide insert 10 is rolled into the cylindrical shape, after the cylindrical shape is formed or during the rolling process. In addition, FIGS. 16 and 19 show non-limiting examples of areas of the outer surface 122 on which the retaining compound 120 can be applied. In other alternate embodiments, the retaining compound 120 can be located on the entire outer surface 122 of the valve guide insert 10 or a different portion of the valve guide insert 10.

As illustrated in FIGS. 16-20, when the valve guide insert 10 having the retaining compound 120 is inserted into the valve guide bore 12, the retaining compound 120 serves to increase the frictional fit between the valve guide insert 10 and the valve guide bore 12. In this manner, when inserted into the valve guide bore 12, the valve guide insert 10 substantially retains its position within the valve guide bore 12 before the broaching process, while other valve guide inserts 10 are being broached and during the broaching of the particular valve guide insert 10. It is contemplated that the retaining compound 120 can be disposed on any one or more of the embodiments of the valve guide insert 10 described herein.

As with previous embodiments discussed herein, the increased frictional fit between the valve guide insert 10 and the valve guide bore 12 allows the user to insert valve guide inserts 10 within all of the valve guide bores 12 to be refurbished as a first step. The broaching tool can then be used in a second step to broach each of the valve guide inserts 10 within the respective valve guide bores 12 without substantial interruption to secure the valve guide inserts 10. Such a two-step process can generally be more efficient and cost effective than repeatedly inserting a single valve guide insert 10 and then broaching that single valve guide insert 10 within the valve guide bore 12 before inserting and broaching the next valve guide insert 10.

In alternate embodiments, other materials can be applied to the other surface of the valve guide insert 10 to increase the frictional coefficient of a portion of the outer surface 122 of the valve guide insert 10. These alternate materials can include, but are not limited to, various adhesives, various particulate matter, or other such materials that can increase the frictional coefficient of at least a portion of the outer surface 122 of the valve guide insert 10.

Referring now to FIGS. 21-25 of the illustrated embodiments, the interference portion of the valve guide insert 10 can also include a textured portion 130 of the outer surface 122 of the valve guide insert 10. The textured portion 130 can include a raised or rough surface, etching patterns, or other surface condition integrally defined within the outer surface 122 of the valve guide insert 10. While the figures show a defined area on the outer surface 122 of the valve guide insert 10 for including the textured portion 130, various embodiments can include the textured portion 130 upon the entire outer surface 122 of the valve guide insert 10 or the textured portion 130 being applied to an alternatively dimensioned portion of the outer surface 122 of the valve guide insert 10. By way of explanation, and not limitation, the textured portion 130 can be configured to have a profile roughness parameter (Ra) of greater than about 32 Ra. It is contemplated that other roughness parameters can be used. The textured portion 130 used in the various embodiments can include an irregularly textured surface, a texture having a regular pattern, or other similarly configured surface condition. In various embodiments, the textured portion 130 can be applied to the outer surface 122 of the valve guide insert 10 during the process of rolling the metallic material into the cylindrical shape that defines the valve guide insert 10. Such an applied material can include an applied grit material, granules, or other applied material. In alternate embodiments, the textured portion 130 can also be applied either before or after this rolling process. In the various embodiments, it is contemplated that any one or more of the embodiments of the valve guide insert 10 described herein can include the textured portion 130 along at least a portion of the valve guide insert 10.

It will be understood by one having ordinary skill in the art that construction of the described invention and other components is not limited to any specific material. Other exemplary embodiments of the invention disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.

It is also important to note that the construction and arrangement of the elements of the invention as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements shown in multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of the wide variety of materials that provide sufficient strength or durability, in any of the wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present invention. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

It is to be understood that variations and modifications can be made on the aforementioned structure and methods without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise. 

The invention claimed is:
 1. A valve guide insert for lining and relining a valve guide bore in an internal combustion engine having a valve with a valve stem, the valve guide bore being configured to support the valve stem for reciprocal motion, the valve guide insert comprising: a one-piece, cylindrically-shaped metallic tube made from reformable bearing material having first and second ends and an intermediate portion extending between the first and second ends; a longitudinal slit disposed along the length of the valve guide insert; an inwardly tapered portion disposed at the first end, wherein a first outer diameter of the inwardly tapered portion is less than an inner diameter of a valve guide bore, and wherein a second diameter of the intermediate section is greater than an inner diameter of a valve guide bore; and an interference portion disposed proximate the second end, wherein the interference portion is configured to substantially secure the valve guide insert within a valve guide bore.
 2. The valve guide insert of claim 1, wherein the interference portion includes a narrowed portion of the longitudinal slit, and wherein the width of the slit at the narrowed portion is less than the width of the slit distal to the narrowed portion, and wherein the longitudinal slit includes a stepped portion.
 3. The valve guide insert of claim 2, wherein the narrowed portion has a substantially consistent width across the longitudinal slit.
 4. The valve guide insert of claim 2, wherein the width of the narrowed portion decreases from a first width proximate the intermediate portion to a second width distal from the intermediate portion.
 5. The valve guide insert of claim 1, wherein the interference portion includes an outwardly flared portion.
 6. The valve guide insert of claim 5, wherein the outwardly flared portion has a consistent thickness.
 7. The valve guide insert of claim 1, wherein the inwardly tapered portion has a consistent thickness.
 8. The valve guide insert of claim 1, wherein an inner surface of the valve guide insert includes a substantially spiral groove defined therein.
 9. A valve guide insert for lining and relining a valve guide bore in an internal combustion engine having a valve with a valve stem, and the valve guide bore being configured to support the valve stem for reciprocal motion, the valve guide insert comprising: a one-piece, cylindrically-shaped metallic tube made from reformable bearing material having first and second ends and an intermediate portion extending between the first and second ends; an inwardly tapered portion disposed at the first end, wherein a first outer diameter of the inwardly tapered portion is less than an inner diameter of the valve guide bore, and wherein a second outer diameter of the intermediate portion is greater than an inner diameter of the valve guide bore; a longitudinal slit disposed along the length of the valve guide insert, wherein the longitudinal slit includes a stepped portion; and an interference portion disposed on at least a portion of an outer surface of the valve guide insert.
 10. The valve guide insert of claim 9, wherein the interference portion includes an integral surface condition having a roughness parameter of greater than about 32 Ra.
 11. The valve guide insert of claim 10, wherein the interference portion includes an applied grit material.
 12. The valve guide insert of claim 9, wherein the interference portion includes an adhesive compound.
 13. The valve guide insert of claim 12, wherein the adhesive compound is an anaerobic adhesive retaining compound.
 14. The valve guide insert of claim 1, wherein the interference portion includes a narrowed portion of the longitudinal slit, and wherein the width of the slit at the narrowed portion is less than the width of the slit distal to the narrowed portion.
 15. The valve guide insert of claim 14, wherein the narrowed portion has a substantially consistent width across the longitudinal slit.
 16. The valve guide insert of claim 14, wherein the width of the narrowed portion decreases from a first width proximate the intermediate portion to a second width distal from the intermediate portion.
 17. The valve guide insert of claim 9, wherein the valve guide insert includes an outwardly flared portion proximate the second end.
 18. The valve guide insert of claim 9, wherein an inner surface of the valve guide insert includes a substantially spiral groove defined therein.
 19. A valve guide insert for lining and relining a valve guide bore in an internal combustion engine having a valve with a valve stem, and the valve guide bore being configured to support the valve stem for reciprocal motion, the valve guide insert comprising: a formed cylindrical tube having a substantially consistent wall thickness, first and second ends, first and second edges that extend between the first and second ends and an intermediate portion defined within the first and second ends and the first and second edges, wherein the cylindrical tube is shaped such that the first and second edges define a longitudinal slit along a length of the cylindrical tube; and an outwardly flared portion of the cylindrical tube is disposed proximate one of the first and second ends.
 20. The valve guide insert of claim 19, further comprising: an interference portion disposed proximate the intermediate portion, wherein the interference portion includes at least one of an integral surface condition and an applied adhesive compound. 